Coupler mechanism for ball-type trailer hitches



3,446,520 COUPLER MECHANISM :FOR BALL-TYPE TRAILER BITCHES Filed July12, 1967 May 27, 1969 c. E. GIBSON ET AL Sheet INVENTORS V06 6. 6/880004/ M. ersesau May 27, 1969 c; E. GIBSON ET AL 3,

I COUPLER MECHANISM FOR BALL-TYPE TRAILER BITCHES Filed July 12, 1967Sheet 2 of z INVENTORS are: E. 6/880 m 07, Persian! Tenn.

Filed July 12, 1967, Ser. No. 652,787

Int. Cl. B60d 1/06, 1/04 7 US. Cl. 280-512 19 Claims ABSTRACT OF THEDISCLOSURE A housing defining a generally spherical cavity which has aside opening communicating with a bottom opening of a diameter smallerthan that of the cavity, with a latch element pivotally mounted withinthe housing so as to have a first pivotal position which surfaces of thelatch element serve to at least partially close the side and bottomopenings of the cavity, to entrap a ball inserted there-within. Thelatch element is pivotal to a second position in which it is removedsufliciently from the aforesaid side and bottom openings of the cavityto admit entrance of a ball thereinto. A spring-loaded plunger ismounted on the housing to engage the latch elements in its first orball-entrapping position, to thereby lock this element in such position.An operating handle is attachedto this plunger for manually retractingit away from the latch element to permit movement of the latter towardits second pivotal position, and this handle may be indexed against thehousing to hold the plunger in its retracted position. The latch elementbears against the retracted plunger when the latch is moved to itssecond position and pushes on the plunger to move it at least a slightamount. This allows a spring to move the operating handle out of itsindexed position against the housing, such that when the latch elementis moved back from its second to its first position the plunger willautomatically be biased into its locking position with respect to thelatch element.

Background of the invention This invention relates to trailer hitchmechanisms of the ball and socket type, and more particularly it relatesto coupling mechanisms defining the socket in which a ball-type hitch isseated and retained. v

The basic principle of the ball and socket-type trailer hitch is verywell known and has been used for a considerable length of time. Manymodifications of this basic principle have heretofore been provided inan attempt to improve on the basic mechanism itself, usually in order tomake the retention of the ball within the socket more positive, or elseto facilitate the ease of connecting and disconnecting the hitch.Generally speaking, these two factors are largely regarded as beingmutually contradictory, in that hitches which provide the most secureretention of the ball are also the most diflicult or time consuming tooperate, whereas hitches which are exceedingly easy to operate typicallydo not retain the ball as securely as might be desired.

Summary of the invention The present invention provides a novel form ofa coupling mechanism for a ball-type hitch which not only entraps andretains the ball with utmost security and dependability, but which alsois exceedingly easy and rapid to operate. The coupler mechanism of theinvention is automated in certain respects, such that certain featuresof its operation occur automatically and without the necessity of anyaccompanying adjustments or manipulations whatever; further, thestructural features of the 3,446,520 Patented May 27, 1969 mechanism areexceedingly uncomplicated and rugged in design, and will provide greatreliability with an absolute minimum of maintenance and/ or repair.

Briefly stated, the coupler mechanism of the invention comprises ahousing means defining a partial socket or chamber for receiving theball hitch, with a movable latch means operable to securely entrap theball within the socket or chamber. A lock is provided for engaging thelatch means and preventing any movement thereof away from itsball-entrapping position, so that the retention of the ball is positiveand absolute. The lock for the latch means is biased so that it alwaystends to engage the latch, and a manually operable handle is providedfor retracting the lock away from the latch means to allow the ball tobe withdrawn from the chamber. The handle is arranged to index and holditself in the position wherein the lock is withdrawn from the latchmeans, so that the ball may be withdrawn at any time after the handle ismoved to its indexing position. Upon withdrawal of the ball, however, apart of the latch means is moved into contact with the lock to therebyrelease the operating handle from its index position and restore it toits normal position, in which the lock may engage the latch meanswhenever the latter is moved back to a ball-entrapping position.Ordinarily, this will occur merely upon reinsertion of a ball into thesocket or chamber, during which the ball itself contacts a portion ofthe latch means to move the same into its ball-entrapping position.Thus, only a single and exceedingly easy action is required to disengagethe ball when it is locked into retention within the chamber, and nooperation or manipulation whatever is required to reengage and lock theball, except to merely insert the ball back into the chamber.

Description of the drawings FIG. 1 is a fragmentary plan view of acoupler mechanism embodying the invention;

FIG. 2 is an enlarged, fragmentary sectional elevation taken through thevertical plane IIII of FIG. 1;

FIG. 3 is a sectional end elevation taken through the plane 1IIIII ofFIG. 2;

FIG. 4 is a fragmentary sectional side elevation similar to FIG. 2 butshowing relative changes of position of certain elements duringoperation of the coupler;

FIG. 5 is a fragmentary sectional side elevation similar to FIGS. 2 and4, but showing other relative position changes of elements duringoperation;

FIG. 6 is a fragmentary sectional side elevation'similar to FIGS. 2, 4,and 5, but showing other relative position changes of elements duringoperation; and

FIG. 7 is a fragmentary sectional side elevation similar to FIGS. 2, 4,5, and 6, but showing other relative position changes of elements duringoperation.

Description 0 a preferred embodiment Referring now in more detail to thedrawings, the coupler mechanism 10 is generally characterized by ahousing 12 of rigid and relatively heavy sheet metal and which isbasically channel-like in section, being open on its underside (FIGS. 1,2, and 3). The housing 12 has a rearward extremity 14 (FIG. 1) withdiverging sides intended to be connected to the conventional frameelements which typically form the tongue by which a trailer is pulled,and the housing also has a protruding forward portion 16 which housesthe latching and looking components of the mechanism. Located atop thehousing portion 16 is an operating handle 18, to be described in moredetail subsequently.

The forward portion 16 of the housing is formed to define a generallyspherical chamber 20 (FIG. 2) which is open at its bottom and at itsrearwardly-facing side.

The housing should extend below the horizontal axis of the sphericalchamber in an arcuate lateral constriction, seen at 21. Above thechamber 20, the forward portion of the housing rises vertically along awall 22 and then smoothly curves rearwardly in a fiat, horizontal topwall 24.

Within the housing, a latching element 26 is pivotally mounted on ashaft 28 which extends between the two upright sides of the forwardportion 16 of the housing (FIGS. 2 and 3). Latching element 26preferably extends almost completely across the distance between the twoside walls of the housing, so as to substantially fill therearwardly-facing side opening of the chamber 20. The latch element 26has a forwardly-facing spherical cavity 30 formed therein, and the pivotshaft 28 for the latch element, which is located above the horizontalaxis of the spherical chamber 20, is positioned so that the concavesurface of the latching element defining its cavity 30 falls on thespherical periphery of the chamber 20 when the latching element is inthe position seen in FIG. 2, referred to herein as it first position. Itis to be noted that the formation of the cavity in the latching elementprovides the latter with a shoulder or edge extremity 31 marking theupper boundary of the chamber 20 and a similar edge portion 32 markingthe lower boundary of the chamber. Extending downwardly and rearwardlyfrom the edge portion 32 is a generally fiat chamferred or bevelledsurface 34 which is arcuate in lateral extent and which is in centralvertical alignment with the cavity 30 (FIG. 3).

Directly above the latching element 26 is a locking means 36 forsecuring the latching element in its aforesaid first position. Morespecifically, locking means 36 includes the operating handle 18 notedpreviously as well as a spring-biased plunger or member 38 which isslidably fitted through an opening in the top wall 24 of the housing, soas to be reciprocable through the housing and with respect to thelatching element 26 upon operation of the handle 18. The plunger member38 is basically T-shaped (FIG. 3), having an enlarged head 39 at itslower extremity which preferably extends substantially completely acrossthe forward portion 16 of the housing. The top portion of the latchingelement 26 has a generally vertical shoulder 40 extending thereacross,and this provides a seat against which the rearwardly-facing side of theplunger head 39 is directly abutted when the plunger is in its firstposition (FIG. 2). It should be noted that in this position, theforwardly-directed side of the plunger head 39 abuts the inner face ofthe vertical wall portion 22 of the housing. It will thus be apparentthat in its aforesaid first position, the plunger positively blocks anycounterclockwise pivotal motion of the latching element 26 away from itsaforesaid first position. For purposes to be stated subsequently, thevertically disposed surface of the shoulder 40, as Well as the matingsurface on the plunger head 39, should be at a slight angle to the truevertical, for example approximately seven degrees.

The locking means 36 also includes a leaf spring element 42 which issecured to the top wall 24 of the housing, as by a rivet 44 or the like,and which extends downwardly against the top of the plunger head 39, tocontinuously bias the plunger downwardly toward the latch element 26.Thus, whenever the latch element is in its first position seen in FIG.2, the plunger head will bias into position between the shoulder 40 ofthe latch element and the vertical wall 22 of the housing. The operatinghandle 18 is pivotally attached to the upper extremity of the plunger 38by a pin 46, and a torsion spring 48 entrained over pin 46 continuouslybiases the operating handle in a clock-wise direction, toward its normalposi tion seen in FIG. 2, in which its fiat bottom extremity lies flushagainst the top wall 24 of the housing.

It will be observed that the forward end 118 of the handle 18 is, likethe bottom of the handle, flat in configuration, and that the handle issmoothly curved at 218 between its fiat end 118 and its fiat bottomextremity. The pivot pin 46 for the handle is offset from the center ofcurvature of the curved portion 218, so that when the handle 18 israised, i.e., moved in a counterclockwise direction to a verticalposition, the curved portion 218 acts as a cam against the top wall 24of the housing to raise the plunger 38 vertically a sufficient distanceto position the head 39 of the plunger above the shoulder 40 of thelatch element 26, thereby unblocking the latch element and permittingcounterclockwise rotation of the latter. Also, the flat configuration ofthe end 118 of the operating handle provides what is referred to as anindexing cam surface which will bear against the top wall 24 of thehousing to hold the plunger 38 in the raised position just described.

In operating the coupler mechanism of the invention, assuming that thelatchingelement 26 and locking means 36 are in the positions show ninFIG. 2, the operating handle 18 is initially raised to the position seenin FIG. 4, wherein the head 39 of the plunger is raised slightly abovethe latch element 26 and clear of the shoulder 40 of the latter, withthe fiat indexing end surface 118 of the operating handle bearingagainst the top wall 24 of the housing and holding the plunger in itselevated or raised position.

Under these circumstances, the latch element 26 is free to rotate in acounterclockwise direction. The ball 50 of a typical ball-type hitch isthen inserted into the spherical chamber 20 (FIG. 5), as by pushing thecoupler mechanism downwardly over the ball. Upon initial insertion ofthe ball 50, the ball contacts the chamferred lower portion 34 of thelatching element and pushes outwardly against the bottom of the latchingelement as the ball rides up the chamfer 34-. This rotates the latchelement 26 in a counterclockwise direction, steadily admitting furtherentry of the ball. This rotation of the latching element brings the topsurface thereof, located at the uppermost extremity of the verticalshoulder 40, into contact with the bottom surface of the plunger head 39whereupon further rotation of the latch element, caused by furtherinsertion of the ball, causes the plunger to be raised, due to thecurved rearward surface 126 of the latch element, which thus acts as acam against the bottom of the plunger head.

When the ball 50 has been inserted to the extent shown in FIG. 5 and isin central-bearing alignment against the lower edged extremity 32 of thelatch element, the latter is pivoted sufiiciently to raise the plunger38 enough to lift fiat indexing cam end 118 of the operating handle 18above the upper wall 24 of the housing. At this point, the torsionspring 48 acting against the underside of the handle 18 causes thehandle to rotate counterclockwise about its pivot pin 46, until it comesinto contact with the top wall of the housing. At this point, the latchelement 26 is the only thing holding the plunger 38 in a raisedposition, since if the latch element were not positioned beneath theplunger the leaf spring 42 would immediately push the plunger downward.

Upon final insertion of the ball 50 into the spherical chamber 20, theball contacts the upper edge extremity 31 (FIG. 6) of the latch elementand bears upwardly threeagainst. This rotates the latch element in aclockwise direction about its pivot pin 28, until at the point where theball has fully entered the spherical chamber 20, the latch element 26will have been rotated back to its aforesaid first position, wherein theball 50 is entrapped within the chamber and the cavity 30 in the latchelement (FIG. 7). In this position of the latch element, the camsurface-126 thereof is no longer beneath the plunger head 39. As soon asthis occurs, the leaf spring 42 snaps the plunger downwardly into itsblocking position with respect to the latch element, i.e., between thevertically disposed shoulder 40 of the latch element and the verticalwall portion 22 of the housing. This of course prevents anycounterclockwise rotation of the latch element and retains the ball 50snugly within the spherical chamber, thereby coupling the ball hitch.For utmost security in maintaining the engagement of the ball 50, alocking pin of a conventional type may be inserted through a pair ofholes such as 52 located in the side walls of the housing 16 immediatelybehind the latch element 26 when the same is in its first position (FIG.7), so that the pin 52 will restrain the bottom portions of thelatchelement from any counterclockwise rotation in the event that the plunger38 somehow becomes broken or inadvertently raised.

Disengagement of the present coupler mechanism from the ball hitch israpidly and easily accomplished. Basically, all that need be done is tolift the operating handle 18 to a vertical position and withdraw theball from the socket or chamber, as by lifting the housing away from theball. When the operating handle '18 is lifted to the vertical positionseen in FIG. 4, the plunger 38 is retracted away from the top of thelatch element 26, and thehandle is held in its vertical position by theabutment of the fiat indexing cam surface 118 thereof against the top ofthe top housing wall 24, as noted previously. Since the latching elementis then no longer blocked from pivotal movement in a counterclockwisedirection, the ball 50 may simply be withdrawn from the socket orchamber 20.

As the ball 50 is drawn downwardly out of the chamber, it steadilypushes against the lower edge extremity 32 of the latch element, therebypivoting the latch element in a counterclockwise direction toward itssecond position, in which the bottom opening of the chamber issufficiently large to allow the ball to be drawn straight downwardly,out of the chamber. After a very brief initial counterclockwise movementof the latching element in this manner toward its second position, thetop of the latching element and the curved cam surface 126 on therear-ward side thereof move beneath the plunger head 39 as before, andas the ball 50 is progressively pulled downwardly with respect to thehousing, the plunger is progressively raised until the flat indexing camsurface 118 of the operating handle is raised sufficiently above the topwall 24 of the housing to permit the torsion spring 48 to move theoperating handle in a clockwise direction, until its end opposite theplunger rests against the top wall of the housing (FIG. 5). This occurswhen the horizontal diameter of the ball is approximately in directalignment with the lower edge portion 32 of the latching element, atwhich point the latching element need not be pivoted backward anyfurther to allow the ball to freely move out of the chamber 20.

When the ball 50 is disengaged from the coupling mechanism in theaforesaid manner, the latching element 26 will remain in its secondposition, because the head 39 of the plunger is pressed firmly downwardagainst the top of the latching element by the leaf spring 42. Thus,when it is desired to once again engage the ball hitch within the socketof the coupling mechanism, the lower extremities of the latching elementare likely to be sufficiently pivoted to allow free entrance of the balluntil the point is reached at which the ball bears upwardly against theupper edge portion 31 of the latching element. Further insertion of theball from this point will thus serve to pivot the latching element in aclockwise direction, so that the lower edge extremity 32 of the latch ismoved to the left to engage the bottom portion of the ball and entrapthe same within the chamber, between latch element edge portion 32 andthe arcuate lateral constriction 21 of the housing. When the ball isfully engaged within the chamber, the latching element will have pivotedsufiicielntly clockwise to allow the downwardly-biased plunger head 39to be moved into its blocking position between the shoulder 40 of thelatching element and the forward vertical wall 22 of the housing. Atthis point the operating handle once again lies flat against the top ofthe housing, even though it was never manually operated in any mannerduring the re-coupling of the ball.

From the foregoing, it will be observed that operation of the presentcoupler mechanism is substantially automatic, i.e., once a ball has beenengaged for the first time within the coupler mechanism, the operatinghandle 18 need be actuated only a single time to permit both the fulldisengagement of the ball as well as the full reengagement thereof at asubsequent time. That is to say, the locking means 36 comprising theopenating handle and the plunger only needs to be retracted to unblockthe latching element; the locking means need not be manually operated atall in order to positively re-engage a ball within the chamber of thec-o-unpler.

Furthermore, the latching element itself is automatically moved by theinsertion and the retraction of the ball hitch itself, and the propermovement of the latching element is entirely safe, accurate, andfoolproof. Also, the blocking of the latching element in itsball-engaging first position is absolutely positive and secure due tothe manner with which the plunger head blocks the latching element,i.e., by being inserted between the housing and the latch element. Inthis regard, the slight vertical angle preferred for the engagingsurfaces of the plunger head 3? and latch element shoulder 40 areintended for the purpose of compensating for manufacturing tolerances inthe exact size of the ball and for wear which may occur in either theball or the spherical cavity 30 formed on.

the front face of the latching element, with a slight wedging operationwhich will be readily understood.

It is entirely conceivable that upon examining the foregoing disclosure,those skilled in the art may devise embodiments of the concept involvedwhich differ somewhat from the embodiment shown and described herein, ormay make various changes in structural details to the presentembodiment. Consequently, all such changed embodiments or variations instructure as utilize the concepts of the invention and clearlyincorporate the spirit thereof are to be considered as within the scopeof the claims appended herebelow, unless these claims by their languagespecifically state otherwise.

We claim:

1. A coupler mechanism for hitching a trailer vehicle to a pullingvehicle by a ball-type hitch, said coupler mechanism comprising incombination: a housing securable to such trailer vehicle and defining apartial chamber with a laterally enlarged upper portion for acceptingsaid ball and a laterally constricted lower portion for fitting aboutthe lower extremities of said ball to partially retain the same Withinsaid chamber; a latching element mova- 'bly carried Within said housing;said latching element having a portion for interfitting with at leastthe lower extremities of a ball located in said chamber when saidlatching element is in a first position, such that said latching elementportion cooperates with said constricted lower portion of said housingchamber to prevent downward retraction of the ball out of said chamber;said latching element also having a second position in which its saidportion is removed from said interfitting relation with said ball; saidlatching element further having an abutment surface thereupon; a lockingmeans including a member having a first position wherein a part of saidmember lies adjacent said latching element abutment surface when saidlatching element is in its first position, to block said latchingelement and prevent movement thereof away from said first position; saidlocking means member also having a second position wherein said latchingelement is unblocked and movable to its second position; said lockingmeans further including an operator component for moving said memberbetween its said two positions; and said latching element having meansfor causing said element to be directly contacted by portions of a ballbeing inserted into said chamber and for causing such element to bepushed into its first position by said ball upon final insertion thereofinto the chamber, whereupon operation 7 of said locking means blockssaid latching element to retain the ball within the chamber.

2. The coupler mechanism of claim 1, wherein said latching element meanswhen said element in its first position and not blocked 'by said lockingmeans member, further causes said latching element to be contacted byportions of a ball being inserted into said chamber and moved by saidball upon further insertion thereof away from its said first position toits said second position, final insertion of said ball into said chamberpushing said latching element back into its first position.

3. The coupler mechanism of claim 1, wherein said locking means includesa biasing element for urging said member toward its said first position,in which the said portions of said member lie adjacent said latchingelement abutment surface to block movement of the element; said lockingmeans operator component arranged to overcome said biasing element inmoving said member to its said second position.

4. The coupler mechanism of claim 1, wherein said locking means memberhas a portion which, when said member is in its first said position,fits between a portion of said housing and the said abutment surface onsaid latching element, to thereby block movement of said element awayfrom its said first position.

5. The coupler mechanism of claim 1, wherein said locking means includesreleasable means for holding said locking means member in its saidsecond position once the latter has been moved into such secondposition.

6. The coupler mechanism of claim 5, wherein said releasable means forholding said locking means member includes an indexing cam surfacedefined by portions of said operator component and arranged to contactand rest against said housing.

7. The coupler mechanism of claim 5, wherein said latching element islocated and carried by said housing such that when in said firstposition and not blocked by said locking means member said latchingelement is contacted by portions of a ball being inserted into saidchamher and moved by further insertion of such ball from said firstposition to said second position, final insertion of said ball into saidchamber moving said latching element back into its first position.

8. The coupler mechanism of claim 7, wherein said latching element andsaid locking means member are located and positioned with respect toeach other such that when said locking means member is in its secondposition, movement of said latching element toward its second positionby said further insertion of said ball into said chamber brings asurface on said latching element into contact with a surface on saidmember to push said member beyond its second position; said releasablemeans for holding said member being released by such pushed movement ofsaid member, such that said member may be returned to its first positionblocking said latching element upon movement of the latter into itsfirst position by said final insertion of said ball into said chamber.

9. The coupler mechanism of claim 8, wherein said locking means includesa biasing element acting upon said locking means member to urge the sametoward its said first position, such that upon release of said means forholding said locking means member in its second position and upon saidlatch element being moved to its first position, said locking meansmember is *biased directly into its first position blocking said latchelement.

10. The coupler mechanism of claim 9, wherein said locking means memberhas a portion which, when said member is in its first said position,fits between a portion of said housing and the said abutment surface onsaid latching element, to thereby block movement of said element awayfrom its said first position.

11. The coupler mechanism of claim 10, wherein said means for releasablyholding said locking means member includes an indexing cam surfacedefined by portions of said operator component and arranged to contactand rest against said housing.

12. The coupler mechanism of claim 11, wherein said locking meansfurther includes a biasing member acting against said operator componentto urge the same toward a position wherein said indexing cam surface isout of contacting alignment with said housing; said locking means memberwhen pushed beyond its second position moving said operator componentcam surface away from said housing; and said biasing member then movingsaid oper ator component such that the said cam surface thereof is movedout of contacting alignment with said housing.

13. In a coupler mechanism for hitching a trailer vehicle to a pullingvehicle, of the type wherein a ball secured to the pulling vehicle ismated with a socket means attachable to the trailer vehicle, theimprovement comprising: a housing defining a generally spherical cavityhaving a side opening communicating with a bottom opening of a diametersmaller than that of the cavity, for admitting a ball thereinto; a latchelement pivotally supported on said housing at the side opening of saidcavity; said latch element having a portion near its bottom and belowits pivotal axis for closing at least part of said bottom cavity openingat a first pivotal position of the latch element, to thereby entrap aball inserted into said cavity; said latch element being pivotable to asecond position wherein said entrapping portion is moved away from saidbottom opening to allow insertion and withdrawal of said ball into andfrom said cavity; means engageable with said latch element in the firstposition thereof to prevent pivotal movement thereof toward said secondposition and thereby ensure the entrapment of said ball; said latchelement having an angularly inclined surface beneath its said portionfor initial contact with a ball being inserted into said chamber, suchthat during initial insertion such ball cams against said inclinedsurface to pivot said latch element toward its second position, to admitentry of the ball; and said latch element having an upper extremityspaced laterally from the pivotal axis of the element, for contact withsaid ball as the same is fully inserted into said cavity; said ball uponfull insertion pushing against said upper extremity to pivot said latchelement back to its said first position.

14. The improvement recited in claim 13, wherein said means engageablewith said latch element to prevent pivotal movement thereof comprises aplunger and a spring biasing said plunger continuously toward saidlatch, such that said plunger will automatically engage said latchwhenever the latter is in its first position; and means for retractingsaid plunger out of engagement with said latch, against the bias actingon said plunger.

15. The improvement recited in claim 14, wherein said means forretracting said plunger comprises an operating handle pivotallyconnected to the plunger and having a cam surface arranged to act on aportion of said housing when said handle is pivoted with respect to saidplunger in a predetermined manner; at least a part of said cam actionmoving said plunger by its connection to said handle to retract theplunger away from said latch element against said bias.

16. The improvement recited in claim 15, wherein said cam surfaceincludes an indexing portion for holding said handle in a fixed positionwherein said plunger is retracted from said latch element.

17. The improvement recited in claim 16, further including a springelement acting on said handle to urge the same toward a position whereinsaid indexing portion of said handle cam surface is out of contactingalignment with said housing.

18. The improvement recited in claim 17, wherein said latch element hasa cam surface arranged to bear against said plunger as said latch ismoved toward its second position and thereby further retract saidplunger to move said indexing portion of said operating handle cam awayfrom said housing; said spring element acting on said handle then movingthe handle upon such further plunger retraction to a handle positionwherein said indexing portion is out of contacting 'alignment with saidhousing, such that upon movement of said latch element back into itsfirst position said spring biasing said plunger will automatically bringthe plunger into engagement with said latch element to hold the same insaid first position.

19. In a coupler mechanism for hitching a trailer vehicle to a pullingvehicle, of the type wherein a ball secured to the pulling vehicle ismated with a socket means attachable to the trailer vehicle, theimprovement comprising: a rigid unitary'housing wall defining agenerally spherical cavity having a side opening communicating with abottom opening of a diameter smaller than that of the cavity, foradmitting a ball thereinto; a latch element pivotally supported on saidhousing at the side opening of said cavity; said latch element having aportion for closing at least part of said bottom cavity opening at afirst pivotal position of the latch element, to thereby entrap a ballinserted into said cavity; said latch element being pivotable to asecond position wherein said entrappingportion is moved away from saidbottom opening to allow insertion and withdrawal of said ball into andfrom said cavity; and blocking means positioned above the pivot axis ofsaid latch element and extending downwardly from the top of the housingwall to said latch element, said blocking means compressively engageablebetween said housing wall and said latch element in the first positionthereof to block pivotal movement thereof toward said second positionand thereby ensure the entrapment of said ball.

References Cited UNITED STATES PATENTS 2,347,033 4/1944 Daton 2805 102,693,970 11/1944 Coleman et al. 280-5 12 LEO FRIAGLIA, PrimaryExaminer.

R. R. SONG, Assistant Examiner.

Disclaimer 3,446,520.-0Zyde 15'. Gibson and Don M. Peterson, Crossville,Tenn. COU- PLER MECHANISM FOR BALLTYPE TRAILER HITCHES. Patent dated May27, 1969. Disclaimer filed Nov. 4, 1969, by the assignee, GeneralProcessing Corporation. Hereby enters this disclaimer to claim 19 ofsaid patent.

[Ofliez'al Gazette February 10, 1.970.]

